San Diego  A crash involving a semi truck and six other vehicles blocked lanes on north Interstate 15 in Scripps Ranch Monday morning and sent several people to hospitals.

The collision was reported at 7:20 a.m. just south of Miramar Road, the California Highway Patrol said.

Seven people were injured in the crash and taken to hospitals via ambulance, a dispatcher with the San Diego Fire-Rescue Department said. At least one of them suffered serious injuries, the dispatcher said.

The two right lanes as well as the Miramar/Pomerado roads off ramp were shut down as emergency crews tended to the injured and removed the wreckage, the CHP said.

The crash tied up traffic for miles, at one point backing it up all the way to Interstate 8.

A traffic alert was issued until all of the lanes were reopened just before 10 a.m.